A new turbidimetric method for assaying serum C-reactive protein based on phosphocholine interaction

Abstract

Background: C-reactive protein (CRP) is able to bind phospholipids (mainly phosphocholine) in the presence of calcium ions. We investigated the use of this property for developing an affordable turbidimetrical CRP assay based on diluted soy oil. Methods: Serum (or heparinized plasma) was mixed with Intralipid ᮋ 20% in Tris-calcium buffer (pH 7.5). After 30 min of incubation at 378C, the CRP-phospholipids complexes were measured by turbidimetry (660 nm/700 nm) with a Cobas 6000 analyzer (Roche). Results were compared with those obtained using a typical immunoturbidimetric method (Roche). Results: Good correlation (r

A new high-sensitive nephelometric method for assaying serum C-reactive protein based on phosphocholine interaction

“…Most hsCRP assays have a lower LOD of < 0.3 mg/L [5]. So, in contrast to the earlier described manual functional CRP assay [18], the present method is suited as a hsCRP assay. In addition, common turbidimetry is not sensitive enough to meet the required sensitivity for hsCRP measurements.…”

“…When compared with the previously described manual functional method [18], the nephelometric assay has two advantages. At first, we were able to automate the manual method using nephelometry with a reaction time of only 12 min.…”

“…The estimated cost of the described functional nephelometric assay would be as low as ± 0.00001 €/test, vs. ± 0.03 €/test for the manual functional assay [18] and ± 1.0 €/test for an immunological test, this is because the assay requires inexpensive reagents, is technically simple and does not require the use of antibodies. In addition, the automated functional method allows a throughput of 112 tests/h.…”

“…Similarly, CRP also produced agglutination of isolated normal very low-density lipoproteins (VLDL) [16,17]. Tugirimana et al developed a manual turbidimetric CRP assay based on this agglutination with phosphocholine using Intralipid 20%, intended for use in Third World district hospitals [18]. However, this method had an analytical sensitivity of only ± 7 mg/L, which is slightly above the reference range (5 mg/L).…”

Role of hepcidin in recombinant human erythropoietin therapy resistance among chronic hemodialysis patients

“…After 30 min of incubation at 37 degrees C, the CRP-phospholipids complexes were measured by turbidimetry (660 nm/700 nm) with a Cobas 6000 analyzer (Roche). Results were compared with those obtained using a typical immunoturbidimetric method (Roche) [9].…”